Fire Alarm Certificates Explained: BS 5839 Design, Commissioning and Servicing

Ask for "the fire alarm certificate" on a commercial building or HMO and you may be handed up to seven different documents, or none at all. A fire detection and alarm system is not certified once. It is certified at each stage of its life, then serviced on a regular cycle.

The two standards

• BS 5839-1:2025 (in force since 30 April 2025, replacing the 2017 edition) covers systems in non-domestic premises: offices, shops, factories, and the common parts of many residential buildings. If you still use 2017-edition forms, it is time to update them.
• BS 5839-6:2019+A1:2020 covers domestic premises, including houses, flats and many smaller HMOs. It uses grades (the type of equipment) and categories (the level of protection).

Which applies depends on the building, its use and what the fire risk assessment calls for.

The certificates

1. Design certificate

Confirms the system has been designed to the relevant part of BS 5839, including the category of system and any agreed variations. It is issued by whoever did the design, who may not be the installer.

2. Installation certificate

Confirms the system has been installed in line with the design and the standard.

3. Commissioning certificate

Confirms the system has been tested end to end and works as designed, with any variations recorded.

4. Acceptance (handover) certificate

Signed by the client or responsible person to confirm they have received the system, the documents and any training needed. It marks the point where responsibility passes to the building's owner or operator.

5. Verification certificate (optional)

An independent third-party check that the system meets the design and the standard. It is often used on large or complex systems.

6. Modification certificate

Issued when an existing system is extended or altered. The 2025 edition of BS 5839-1 added a section on extensions and modifications.

7. Inspection and servicing certificate

Issued after every routine service. BS 5839-1:2025 recommends servicing every six months, with a tolerance of one month either side, so each visit falls 5 to 7 months after the last. This is the certificate people most often ask for, and the one that most often goes missing.

On small jobs, one engineer may handle design, installation and commissioning and issue a combined certificate. On larger projects, different people sign each stage.

Why servicing records matter

In England and Wales, the Regulatory Reform (Fire Safety) Order 2005 puts duties on the "responsible person" for non-domestic premises and the common parts of buildings with two or more homes. If something goes wrong, the fire authority will want evidence that the system was maintained: a run of servicing certificates, logbook entries, and records of any faults and how they were fixed. Scotland and Northern Ireland have their own fire safety laws.

For landlords, many councils' HMO licence conditions require fire alarm servicing certificates to be produced on demand or at set intervals. Check your licence.

Common gaps

• No commissioning certificate, so nobody can prove the system ever worked as designed.
• Variations not recorded, such as a detector left out of a room without explanation.
• Gaps in the servicing history, such as a missed six-monthly visit.
• Faults logged but never closed.
• The wrong category: the fire risk assessment asks for one level of protection and the system installed gives a lower one.

Issuing fire alarm certificates with CertBox

CertBox for fire safety engineers includes the BS 5839 certificates for each stage above, alongside the other compliance certificates trades and landlords need:

• Fill in certificates on site, free, with set fields for system category, devices tested and variations.
• Send a professional PDF by secure link. Getting a certificate out needs Pro, the 14-day trial or a one-off payment. The responsible person, landlord or agent does not need an account.
• A QR code on every certificate, so a fire officer or licensing team can confirm it is genuine and unaltered.
• Renewal reminders on Pro, so customers are reminded before the next service is due.
• Quotes, invoices and scheduling in the same place.

For landlords and managing agents

If your fire alarm contractor issues certificates through CertBox, you get a link as soon as each one is done. Add them to the property in your landlord account, alongside your gas and electrical certificates. A weekly email flags anything due in the next 60 days, so a missed service does not creep up on you.

Frequently asked questions

How often does a fire alarm need servicing?

BS 5839-1:2025 recommends servicing every six months, with a tolerance of one month either side. Domestic systems under BS 5839-6 have their own recommendations depending on the grade. Follow the installer's guidance and any licence conditions.

Who can issue a fire alarm certificate?

A competent person. In practice, that is a fire alarm engineer with the right training, and often third-party certification for the type of work.

Do battery smoke alarms in a single let need a certificate?

Not usually. In England, landlords must provide working smoke alarms on each storey, plus a carbon monoxide alarm in any room with a fixed combustion appliance (not counting gas cookers), but a formal BS 5839 certificate is usually a requirement for HMOs and larger buildings with installed systems.

What is the difference between a fire alarm certificate and a fire risk assessment?

The certificate covers the alarm system. The fire risk assessment looks at the whole building's fire risks, including escape routes, doors, lighting and management, and often says what alarm system is needed.

Sources

Checked against these on 2026-10-20.

• FIA: Guide to the changes in BS 5839-1:2025 (PDF)
• NSI 005-25: Publication of BS 5839-1:2025 (PDF)
• IET Wiring Matters: Key changes to BS 5839-1:2025, part 2
• NSI Technical Bulletin 0047: Publication of BS 5839-6:2019 (PDF)
• GOV.UK: Fire Safety Order 2005, supplement to guidance note 1 (enforcement)
• GOV.UK: Smoke and carbon monoxide alarms, explanatory booklet for landlords

Corrected and updated 2026-10-20. This article is for general guidance only and does not constitute legal or professional advice. Always refer to the relevant standards and consult qualified professionals for definitive requirements.